Devices and methods for bending or cutting implants

ABSTRACT

Devices and methods for bending or cutting implants are disclosed herein. In some embodiments, an instrument can convert a rotational input force (e.g., supplied by a powered driver tool) into movement of a first rod holder with respect to a second rod holder. Such movement can form a bend in a rod or other implant held by the first and second rod holders. Various mechanisms for converting this movement are disclosed, such as a worm drive mechanism and a conical gear mechanism, as are various types of rod holders, including orbiting rollers, lid-type rod holders, fixed and pivoting half-pipe rod holders, and full-pipe rod holders. In some embodiments, the instrument can also be used for cutting, for example by rotating a cutting wheel with respect to a cutting plate to cut a rod or other implant inserted through openings formed in the cutting wheel and the cutting plate.

FIELD

Devices and methods for bending or cutting implants are disclosedherein.

BACKGROUND

There is often a need to bend or cut an implant during a surgicalprocedure or in preparation for a surgical procedure. For example,spinal rods are typically cut to a desired length and bent to a desiredshape before being implanted in a patient. Often times, several bendsare necessary to form a compound or complex bend along the length of alarge rod. Forming the final shape can be an iterative process in whichthe rod is bent, checked for fit, and then bent again until the desiredshape is achieved.

Existing solutions for bending or cutting rods have numerousshortcomings. The bending and cutting tools used today are very largeand are not capable of bending a rod that is at least partiallyimplanted in the patient. Instead, these tools are typically used at aback table in the operating room, remote from the patient and thesurgical site. As a result, the surgeon usually needs to make severaltrips back and forth between the patient and the back table to makeadjustments until the final rod shape is achieved. Existing tools alsorequire significant input force from the surgeon, which increasessurgeon fatigue. These tools also lack precision, which increases thenumber of adjustments that must be made to the rod. In some cases,repeated bending and adjustment of the rod can reduce the rod strength.

There is a continual need for improved bending and/or cutting devicesand related methods.

SUMMARY

Devices and methods for bending or cutting implants are disclosedherein. In some embodiments, an instrument can convert a rotationalinput force (e.g., supplied by a powered driver tool) into movement of afirst rod holder with respect to a second rod holder. Such movement canform a bend in a rod or other implant held by the first and second rodholders. Various mechanisms for converting this movement are disclosed,such as a worm drive mechanism and a conical gear mechanism, as arevarious types of rod holders, including orbiting rollers, lid-type rodholders, fixed and pivoting half-pipe rod holders, and full-pipe rodholders. In some embodiments, the instrument can also be used forcutting, for example by rotating a cutting wheel with respect to acutting plate to cut a rod or other implant inserted through openingsformed in the cutting wheel and the cutting plate.

In some embodiments, an instrument for bending an implant includes achassis having a drive shaft disposed therein, the drive shaft beingconfigured to rotate a gear rotatably mounted to the chassis; a firstrod holder mounted on the gear and configured to receive a portion of animplant therein; and a second rod holder mounted on the chassis andconfigured to receive a portion of an implant therein; wherein rotationof the gear causes the first rod holder to move relative to the secondrod holder to form a bend in an implant received in the first and secondrod holders.

The drive shaft can rotate about a first axis and the gear can rotateabout a second axis, the second axis being perpendicular to a plane inwhich the first axis lies. The gear can include a worm gear and thedrive shaft can include a worm screw configured to rotate the worm gearwhen the drive shaft rotates. The gear can include a first conical gearand the drive shaft can include a second conical gear enmeshed with thefirst conical gear. The first rod holder can include a main roller and asecondary roller configured to orbit the main roller when the gearrotates. At least one of the main roller and the secondary roller caninclude an annular groove formed therein for receiving an implant. Atleast one of the main roller and the secondary roller can include aplurality of arcuate portions, each arcuate portion having a differentradius of curvature. The instrument can include a cutting plate havingan implant opening formed therein. The main roller can include animplant opening formed therein. Rotation of the main roller relative tothe cutting plate can be effective to cut an implant extending throughthe implant openings of the main roller and the cutting plate. The firstrod holder can include a half-pipe fixedly mounted to the gear. Thefirst rod holder can include a half-pipe rotatably mounted to the gear.The second rod holder can include first and second mounts with a lidpivotally attached thereto. The first and second mounts can includerespective rod seats. The lid can have an open position in which animplant can be freely moved with respect to the rod seats and a closedposition in which the lid holds the implant in contact with the rodseats. The lid can include opposed pivot pegs that slide withinrespective slots formed in the first and second mounts. The lid caninclude opposed locking pegs that are received within respective firstrecesses of the first and second mounts when the lid is in the openposition and that are received within respective second recesses of thefirst and second mounts when the lid is in the closed position.

In some embodiments, a method of bending an implant using a bendinginstrument having a drive shaft, a gear, and first and second rodholders, includes positioning the implant such that it is received inthe first and second rod holders; and rotating the drive shaft to causethe gear to rotate; wherein rotation of the gear causes the first rodholder to move relative to the second rod holder to form a bend in theimplant.

The first rod holder can include a main roller and a secondary roller.Rotating the gear can cause the secondary roller to orbit the mainroller to bend the implant disposed therebetween. The method can includeselecting one of a plurality of arcuate portions of the main roller andpositioning the selected arcuate portion in contact with the implantbefore bending the implant. The method can include cutting the implantby inserting the implant through a first opening formed in an axleportion of the gear and a second opening formed in a cutting plate ofthe instrument and then rotating the gear relative to the cutting plate.Positioning the implant in the second rod holder can include closing alid of the second rod holder over the implant to lock the implant tofirst and second seat portions of the second rod holder. The first rodholder can include a half-pipe. Rotating the gear can cause thehalf-pipe to pivot relative to the gear as the implant is bent.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description is provided with the accompanyingdrawings, in which:

FIG. 1A is a perspective view of an instrument for cutting and bendingan implant;

FIG. 1B is profile view of the instrument of FIG. 1A;

FIG. 1C is an exploded perspective view of the instrument of FIG. 1A;

FIG. 1D is a profile view of the instrument of FIG. 1A coupled to adriver tool;

FIG. 1E is an exploded perspective view of the chassis of the instrumentof FIG. 1A;

FIG. 1F is an exploded perspective view of the drive shaft of theinstrument of FIG. 1A;

FIG. 1G is a profile view of the instrument of FIG. 1A with amulti-radius main roller;

FIG. 1H is a perspective view of the multi-radius main roller of FIG.1G;

FIG. 1I is an exploded perspective view of a rod holder of theinstrument of FIG. 1A;

FIG. 1J is a perspective view of the rod holder of FIG. 1I in an openconfiguration;

FIG. 1K is a profile view of the rod holder of FIG. 1I in the openconfiguration;

FIG. 1L is perspective view of the rod holder of FIG. 1I in a closedconfiguration;

FIG. 1M is profile view of the rod holder of FIG. 1I in the closedconfiguration;

FIG. 1N is a perspective view of the instrument of FIG. 1A having a roddisposed therein prior to actuation;

FIG. 1O is a perspective view of the instrument of FIG. 1A bending a roddisposed therein;

FIG. 1P is a perspective view of the instrument of FIG. 1A having a bentrod disposed therein after retraction of a secondary roller;

FIG. 2A is a perspective view of an instrument for cutting and bendingan implant;

FIG. 2B is a profile view of a half-pipe of the instrument of FIG. 2A;

FIG. 2C is a plan view of the half-pipe of FIG. 2B;

FIG. 2D is a perspective view of a fixed half-pipe that can be used withthe instrument of FIG. 2A;

FIG. 2E is an exploded perspective view of the half-pipe of FIG. 2D anda worm gear of the instrument of FIG. 2A;

FIG. 2F is a perspective view of a pivoting half-pipe that can be usedwith the instrument of FIG. 2A;

FIG. 2G is an exploded perspective view of the half-pipe of FIG. 2F anda worm gear of the instrument of FIG. 2A;

FIG. 2H is a perspective view of the instrument of FIG. 2A having a roddisposed therein prior to actuation;

FIG. 2I is a perspective view of the instrument of FIG. 2A bending a roddisposed therein using a fixed half-pipe;

FIG. 2J is a perspective view of the instrument of FIG. 2A bending a roddisposed therein using a pivoting half-pipe;

FIG. 3A is a profile view of an instrument for cutting and bending animplant;

FIG. 3B is a plan view of the instrument of FIG. 3A; and

FIG. 4 is a perspective view of a driver tool.

DETAILED DESCRIPTION

Devices and methods for bending or cutting implants are disclosedherein. In some embodiments, an instrument can convert a rotationalinput force (e.g., supplied by a powered driver tool) into movement of afirst rod holder with respect to a second rod holder. Such movement canform a bend in a rod or other implant held by the first and second rodholders. Various mechanisms for converting this movement are disclosed,such as a worm drive mechanism and a conical gear mechanism, as arevarious types of rod holders, including orbiting rollers, lid-type rodholders, fixed and pivoting half-pipe rod holders, and full-pipe rodholders. In some embodiments, the instrument can also be used forcutting, for example by rotating a cutting wheel with respect to acutting plate to cut a rod or other implant inserted through openingsformed in the cutting wheel and the cutting plate.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments.

FIGS. 1A-1P illustrate an exemplary embodiment of an instrument 100which can be used to bend an implant or another object, for example, animplantable spinal rod. As shown, the instrument 100 can include achassis 102, a drive shaft 104, a worm gear 106, a first rod holder 108rotatably mounted to the chassis, a second rod holder 110 fixed to thechassis, and a cutting plate 112. The first rod holder 108 can include amain roller 114 and a secondary roller 116. In use, a rod can bepositioned between the main roller 114 and the secondary roller 116,while being held in place by the second rod holder 110. The drive shaft104 can be driven to rotate the worm gear 106 and cause the secondaryroller 116 to orbit the main roller 114. As the secondary roller 116orbits the main roller 114, a bending force can be applied to the rod tobend the rod to a desired degree at a chosen location. The instrument100 can also be used to cut the rod. For example, the rod can beinserted through an axle portion of the worm gear 106 and through thecutting plate 112, and the drive shaft 104 can be rotated to turn theworm gear with respect to the cutting plate, thereby applying a shearforce to the rod to cut or sever the rod.

The chassis 102 can serve as the main body of the instrument 100 towhich other components are coupled. The chassis 102 can define a centrallumen in which the drive shaft 104 is rotatably disposed. A retentionring or washer 118 can be mounted in corresponding grooves formed in thedrive shaft 104 and the interior of the chassis 102 to maintain thedrive shaft at a fixed longitudinal position with respect to thechassis. Alternatively, or in addition, the chassis 102 can include anend cap 120 for holding the drive shaft 104 within the chassis.

A proximal end of the chassis 102 can include a mating feature forcoupling the instrument 100 to a driver tool (e.g., a manual, electric,hydraulic, or pneumatic drill or driver tool). An exemplarybattery-powered driver tool 400 is shown coupled to the instrument 100in FIG. 1D and is described further below with respect to FIG. 4. Theillustrated chassis 102 is configured for use with a driver tool thatincludes a rotating component sized to fit within a proximal cylindricalopening of the chassis to engage a drive feature 122 formed at theproximal end of the drive shaft 104. The chassis 102 is non-rotatablycoupled to a non-rotating component of the driver tool. Accordingly,when the driver tool is actuated, the drive shaft 104 rotates relativeto a handle portion of the driver tool while the chassis 102 remainsstationary with respect to the handle portion of the driver tool. Thechassis 102 can include one or more pins or other anti-rotation featuresto prevent the chassis from rotating relative to the driver tool. Thechassis 102 can include a chassis extension 124 to which the worm gear106 can be rotatably mounted. The chassis extension 124 can be disposedat the distal end of the chassis 102 and can extend radially outwardtherefrom.

The drive shaft 104 can be an elongate cylindrical rod having proximaland distal ends. In operation, the drive shaft 104 can rotate about arotation axis R1. The drive shaft 104 can include a threaded portion orworm screw 126. The worm screw 126 can be formed integrally with thedrive shaft 104. In the illustrated embodiment, however, the worm screw126 is formed as a separate sleeve component in which the drive shaft104 is received. The longitudinal position of the worm screw 126 withrespect to the drive shaft 104 can be fixed by first and secondretaining caps 128. As shown in FIG. 1F, at least one of the retainingcaps 128 can be formed integrally with the drive shaft 104. Therotational position of the worm screw 126 with respect to the driveshaft 104 can be fixed by an elongated tab or key 130 that sits withincorresponding grooves formed in the exterior surface of the drive shaftand the interior surface of the worm screw 126.

The drive shaft 104 can be mounted in proximal and distal bearingassemblies disposed within the chassis 102 to facilitate rotation of thedrive shaft relative to the chassis. As shown in FIG. 1F, the first andsecond retaining caps 128 can include reduced-diameter shaft portions132 over which the bearing assemblies are mounted. While any of avariety of bearing assemblies can be used, the illustrated bearingassemblies are race bearings that include an outer race 134, an innerrace 136, and at least one ball bearing 138 disposed within respectiveannular tracks formed in the outer and inner races. The race bearingscan also include proximal and distal retaining washers 140. The outerraces 134 can be press fit or otherwise coupled to the chassis 102 andthe inner races 136 can be press fit or otherwise coupled to theretaining caps 128 such that rotation of the drive shaft 104 relative tothe chassis 102 causes the inner race 136 to rotate relative to theouter race 134, with the ball bearing 138 reducing the frictionassociated with said rotation.

The worm gear 106 can have a plurality of teeth formed on an exteriorcircumferential surface thereof. The teeth of the worm gear 106 canengage the threaded portion of the drive shaft 104 such that therotation of the drive shaft 104 about the axis R1 causes the worm gearto rotate about its central axis R2. As shown in FIG. 1A, the axis R2can extend substantially perpendicular to a plane in which the axis R1lies. The worm gear 106 and the drive shaft 104 can form a worm drive inwhich the teeth of the worm gear 106 form the worm wheel and thethreaded portion 126 of the drive shaft 104 forms the worm screw. Thesize, number, and spacing of the teeth, as well as the size of the wormgear 106, can be selected to increase or decrease the torque applied tothe worm gear 106 or the rotating speed of the worm gear 106.

As noted above, the instrument can include a first rod holder 108defined by a main roller 114 and a secondary roller 116.

As shown in FIG. 1C, the main roller 114 can include an axle portion 142and a roller portion 144. The axle portion 142 can be rotatably mountedin an opening 146 formed in the chassis 102. The main roller 114 can berotationally fixed to the worm gear 106. For example, an elongated tabor key 148 can sit within corresponding grooves formed in the exteriorsurface of the main roller and the interior surface of the worm gear 106to lock the main roller to the worm gear. Alternatively, the worm gear106 can be formed integrally with the main roller 114, or can beconfigured to rotate relative to the main roller. A circlip or otherretaining member 150 can be seated within a groove formed in the axleportion 142 to retain the axle portion within the opening 146 formed inthe chassis 102. The axle portion 142 can include at least one hole orthrough-bore 152 in which an implant can be received. For example, asshown in FIG. 1B, the axle portion 142 can include three through-bores152. It will be appreciated that the axle portion 142 can include anynumber of through-bores for receiving an implant therethrough. Asdescribed further below, the openings 152 formed in the axle portion 142can allow the axle portion to act as a cutting wheel for cutting animplant extending through the axle portion and through the cutting plate112.

The roller portion 144 of the main roller 114 can be disposed at thecenter of the worm gear 106 or can be offset from the center of the wormgear. The roller portion 144 can be formed integrally with the axleportion 142 of the main roller 114, or can be a separate componentselectively attached to the axle portion and/or to the worm gear 106.The roller portion 144 can be configured to rotate about its centralaxis with respect to the worm gear 106, or can be rotationally-fixedwith respect to the worm gear.

The roller portion 144 can include an annular recess or groove 154 thatdefines a bending surface for contacting a rod disposed between the mainroller 114 and the secondary roller 116. The groove 154 can have across-sectional shape that forms a section of a circle, as shown, or canhave various other cross-sectional shapes, such as oval, oblong, square,triangular, and so forth. In some embodiments, the cross-sectional shapeof the groove 154 can correspond with the cross-sectional shape of animplant that is to be bent by the instrument 100. The diameter of thegroove 154 can be varied to support bending of rods having differentdiameters.

The roller portion 144 and/or the entire main roller 114 can beinterchangeable. This can allow the roller portion 144 to be removedfrom the instrument 100 and replaced with another roller portion havinga different geometry, e.g., a different diameter, groove shape, or thelike. Varying the geometry of the roller portion 144 can alter thedegree or shape of the resulting bend formed in the rod. For example, amain roller 114 that has a larger diameter can produce a more gradualbend than a main roller with a smaller diameter. The instrument 100 canbe provided as part of a kit that includes a plurality of rollerportions 144, each having a different geometry. In use, the rollerportion 144 having the geometry necessary for forming the desired bendcan be selected from the kit and coupled to the instrument 100 forbending the rod.

A single main roller 114 can also have a geometry that varies along itscircumference such that the same main roller can be used to formmultiple types of bends. For example, a single main roller 114 caninclude two or more varying radii of curvature. As illustrated in FIGS.1G and 1H, a multi-radius main roller 114 can include two or morearcuate portions 156, each arcuate portion having a different radius ofcurvature. A multi-radius main roller 114 can allow the user to selectan arcuate portion 156 that can achieve a specific degree of bending ina rod without replacing the main roller in the device 100. Themulti-radius main roller 114 can have any number of arcuate portions 156to provide the user with options for bending a rod. As illustrated inFIG. 1H, a multi-radius main roller 114 can include three arcuateportions 156A, 156B, 156C, each arcuate portion having a progressivelylarger radius of curvature.

In some embodiments, the main roller 114 can have an adjustable outerdiameter that can be expanded or contracted with manipulation by theuser. For example, a main roller 114 can include concentric circularportions of varying diameters and can be moved relative to the worm gear106 to position a portion having the desired diameter in contact withthe rod.

The secondary roller 116 can include an annular recess or groove 158formed therein that defines a bending surface for contacting a roddisposed between the main roller 114 and the secondary roller 116. Thegroove 158 can thus engage an opposite side of a rod that is disposedwithin the groove 154 of the main roller 114. The secondary roller 116can be mounted to the worm gear 106 such that the secondary rollerorbits the main roller 114 when the worm gear rotates. The secondaryroller 116 can be positioned relative to the main roller 114 so as toallow a rod positioned therebetween to contact the main roller 114 andthe secondary roller 116 simultaneously.

The secondary roller 116 can be rotatably mounted to the worm gear 106such that it can rotate about its central axis R3 with respect to theworm gear. Alternatively, the secondary roller 116 can berotationally-fixed relative to the worm gear. In the illustratedembodiment, the secondary roller 116 is secured to the surface of theworm gear 106, though the secondary roller can also be elevated suchthat it is offset from the surface of the worm gear. The secondaryroller 116 can be mounted to the worm gear 106 by a pivot pin 160 thatextends through a central bore of the secondary roller. The secondaryroller 116 can have varying geometries and a variety of differentsecondary rollers can be interchangeably coupled to the instrument 100,in the same manner as described above with respect to the main roller114.

The cutting plate 112 can be formed integrally with the chassis 102 orcan be coupled thereto as shown. As shown in FIG. 1C, the cutting plate112 can include a disc-shaped plate having at least one opening 162formed therein in which a rod to be sheared or cut can be received. Anyof a variety of techniques can be used to attach the cutting plate 112to the chassis 102. For example, the cutting plate 112 can include oneor more openings in which a screw or bolt can be received to secure thecutting plate to the chassis 102. The cutting plate 112 can berotationally fixed relative to the chassis 102.

To cut an implant, the main roller 114 can be positioned such that atleast one of the openings 152 formed therein is aligned with the opening162 of the cutting plate 112. An implant (e.g., a spinal rod) that is tobe cut can be inserted through the opening 152 of the main roller 114and through the opening 162 formed in the cutting plate 112. A user canthen actuate a driver tool to which the instrument 100 is coupled torotate the drive shaft 104 and the worm screw 126. Rotation of the wormscrew 126 can cause the worm gear 106 to rotate relative to the chassis102 and relative to the cutting plate 112, which is rotationally fixedto the chassis 102. Accordingly, the sidewalls of the openings 152, 162exert a shear force on the rod inserted therethrough, cutting orsevering the rod. In some embodiments, the sidewalls of one or more ofthe openings 152, 162 can be tapered or ramped to provide sharpenedportion(s) (e.g., at the cutting interface between the worm gear 106 andthe plate 112).

The openings 152, 162 formed in either the worm gear 106 or the cuttingplate 112 can be elongated to further increase the number of rotationalpositions of the worm gear at which the opening 152 is aligned with anopening 162 of the cutting plate. The openings 152 can have any of avariety of other shapes (e.g., trapezoidal, ramped or blade-shaped,bean-shaped, etc.). The openings in the cutting plate 112 can beelongated instead, or in addition to the openings in the worm gear 106.The worm gear 106 and/or the cutting plate 112 can include rod openingsof various sizes to facilitate use of the instrument with rods havingvarious sizes (e.g., rods having different diameters). As noted above,the cutting plate 112 can be formed integrally with the chassis 102. Inother words, the cutting plate 112 can be omitted and the chassis 102itself can serve as the cutting plate. Further details on cutting andother features that can be included in the instrument 100 are disclosedin U.S. application Ser. No. 14/723,263, filed on May 27, 2015, entitled“DEVICES AND METHODS FOR BENDING OR CUTTING IMPLANTS,” which is herebyincorporated herein by reference in its entirety.

The second rod holder 110 can be configured to hold at least a portionof a rod that is to be bent in a fixed position relative to the chassis102. An exemplary rod holder 110 is shown in detail in FIGS. 1I-1M. Asshown, the rod holder 110 can include one or more mounts 164 and a lid166. The lid 166 can be pivoted relative to the mounts 164 between afirst, open position (shown in FIGS. 1J-1K) and a second, closedposition (shown in FIGS. 1L-1M). In the open position, the lid 166 ispivoted away from the mounts 164 to allow a rod to be introduced intorod seats 168 formed in each of the mounts. In the open position, a rodthat is to be bent can be free to translate and/or rotate with respectto the rod holder 110. In the closed position, the lid 166 can be closedover a rod that is to be bent, such that the lid holds the rod incontact with the rod seats 168. In the closed position, the rod holder110 can restrict or prevent translation and/or rotation of the rodrelative to the chassis 102.

Each mount 164 can include a rod seat 168, an engagement portion 170 forsecuring the mount to the chassis 102, and features for allowing the lid166 to pivot relative to the mount and to be secured in either thelocked position or the released position. In the illustrated embodiment,these features include an elongate slot 172 and first and secondrecesses 174, 176 disposed at opposite ends of the slot.

The rod seat 168 can be defined by opposed arms that define arod-receiving recess therebetween. The rod seat 168 can be oriented atvarious angles with respect to the chassis 102, but in the illustratedembodiment, the rod seat is positioned such that a portion of a roddisposed therein has a central longitudinal axis that is parallel to thecentral longitudinal axis R1 of the chassis 102.

The engagement portion 170 can be a ring-shaped strap that secures themount 164 to the chassis 102. The engagement portion 170 can beconfigured to receive the chassis 102 therethrough, such that theengagement portion extends around at least a portion of thecircumference of the chassis. One or more openings can be formed in theengagement portion 170 to receive a pin, detent, or other feature forsecuring the engagement portion to the exterior surface of the chassis102. Alternatively, or in addition, the mount 164 can be attached to thechassis 102 by a screw, bolt, press-fit, snap-fit, magnet, weld, strap,clamp, or the like. While two mounts 164 are shown, the rod holder 110can include any number of mounts for attaching the rod holder to thechassis 102.

The lid 166 can include a first end and a second end. The first end ofthe lid 166 can include opposed pivot pegs 178. The pegs 178 can extendlaterally outward from the sidewalls of the lid 166. The pegs 178 can beslidably and rotatably received in the slots 172 formed in the mounts164, such that the lid 166 can pivot with respect to the mounts about acentral axis of the pegs 178 and such that the lid can translate withrespect to the mounts by sliding the pegs within the slots.

The second end of the lid 166 can be configured to capture a rod betweenthe lid and the rod seats 168 of the mounts 164. The second end of thelid 166 can be curved as shown, such that the underside of the liddefines a semi-cylindrical rod seat. The second end of the lid 166 caninclude opposed locking pegs 180. The pegs 180 can extend laterallyoutward from the sidewalls of the lid 166. The locking pegs 180 can bereceived within the first recesses 174 or the second recesses 176 of themounts 164 to secure the lid in the open position or the closedposition, respectively.

As shown in FIGS. 1J-1K, the lid 166 can be moved to the open positionby rotating the lid about the axis of the pivot pegs 178 and sliding thepivot pegs to a bottom end of the slot 172. The lid 166 can bemaintained in the open position by seating the locking pegs 180 withinthe first recesses 174 of the mounts 164. As shown in FIGS. 1L-1M, thelid 166 can be moved to the closed position by rotating the lid aboutthe axis of the pivot pegs 178 and sliding the pivot pegs to a top endof the slot 172. The lid 166 can be maintained in the closed position byseating the locking pegs 180 within the second recesses 176 of themounts 164.

Use of the instrument 100 to bend a rod R is shown in FIGS. 1N-1P. Inthe example shown, an initially straight rod R is to be bent such that adistal portion of the rod extends at an oblique angle with respect to aproximal portion of the rod. It will be appreciated that the instrument100 can be used to form bends having different shapes, and can formbends in rods that already have one or more bends formed therein.

As shown in FIG. 1N, the rod R can be secured to the instrument 100using the first and second rod holders 108, 110. In particular, a distalportion of the rod R can be positioned between the main and secondaryrollers 114, 116 of the first rod holder 108. The rod R can belongitudinally translated and/or axially rotated to position a portionof the rod where the inner bend radius is to be formed against theannular groove 154 of the main roller 114, and to position a portion ofthe rod where the outer bend radius is to be formed against the annulargroove 158 of the secondary roller 116. In the illustrated embodiment,the rod R is in contact with both the main roller 114 and the secondaryroller 116, though a gap can exist between the rod and the rollersbefore and/or after the rod is bent. Further, as previously discussed,the main roller 114 can be rotated, adjusted, and/or replaced withanother roller to vary the shape and/or radius of the resulting bend inthe rod.

Once the rod R is positioned as needed to achieve the desired bend, aproximal portion of the rod can be secured to the second rod holder 110.The lid 166 (not shown in FIGS. 1N-1P for clarity) of the second rodholder 110 can be positioned initially in the open position of FIGS.1J-1K and the rod R can be seated in the rod seats 168 of each mount164. The lid 166 can then be moved to the closed position of FIGS. 1L-1Mto capture the rod R between the lid and the rod seats 168, therebyrestricting or preventing movement of the rod with respect to thechassis 102.

As shown in FIG. 1O a driver tool to which the instrument 100 is coupledcan be actuated to rotate the drive shaft 104 about the axis R1.Rotation of the drive shaft 104 can cause the worm gear 106 to rotateabout the axis R2, thereby causing the secondary roller 116 to orbit themain roller 114 in the direction of arrow D1 to form a bend in the rodR.

After bending the rod R, as shown in FIG. 1N, the driver tool can beactuated to rotate the drive shaft 104 in the opposite direction, thuscausing the secondary roller 116 to orbit the main roller 114 in thedirection of arrow D2. This can allow the secondary roller 116 to bemoved out of engagement with the rod R, e.g., to allow the bent rod tobe removed from the instrument 100.

The steps above can be repeated any number of times with the instrument100 being repositioned along the rod R as needed to form any number ofbends in the rod. The instrument 100 can include markings or indicia fordisplaying to the user the degree to which the rod R has been bent. Forexample, a series of bend angle markings can be printed, engraved orotherwise formed on the worm gear 106 to illustrate to the user thedegree of bending.

FIGS. 2A-2J illustrate another exemplary embodiment of an instrument 200for bending and/or cutting an implant. Except as indicated below and aswill be readily appreciated by one having ordinary skill in the art, thestructure and function of the instrument 200 is substantially the sameas that of the instrument 100 described above, and therefore a detaileddescription is omitted here for the sake of brevity.

As shown, the first rod holder 208 can include a first half-pipe insteadof or in addition to the orbiting rollers described above. As alsoshown, the second rod holder 210 can include a second half-pipe insteadof or in addition to the lid-type rod holder described above. While notshown, various combinations of these features can also be used. Forexample, a half-pipe rod holder can be used to secure the rod to thechassis 202 and an orbiting roller rod holder can be used to secure therod to the worm gear 206. By way of further example, a lid-type rodholder can be used to secure the rod to the chassis 202 and a half-piperod holder can be used to secure the rod to the worm gear 206.

The first half-pipe 208 can include a base portion 214 and a top portion216. The top portion 216 can include opposed arms that define arod-receiving recess 218 therebetween. The recess 218 can have a centralaxis R4. As shown in FIG. 2B, the inner surfaces of the arms can taperor curve inward, such that a width W_(T) of the recess 218 at the freeends of the arms is less than a width W_(B) at the lower portion of thearms where the rod is seated. This can help prevent the rod fromslipping out of the half-pipe 208. In some embodiments, the width W_(T)at the free ends of the arms can be less than the diameter of the rod,such that the arms deflect slightly as the rod is inserted and such thatthe rod snap-fits into the recess 218. While not shown, the firsthalf-pipe 208 can include a lid, set screw, or other closure mechanismfor securing a rod in the recess 218. As shown in FIG. 2C, the recess218 can have curved longitudinal sidewalls such that the width W of therecess varies along the length L of the recess. The recess 218 can thushave a width W_(C) at a central portion of the recess that is less thanthe width W_(E) of the recess at opposed endportions thereof. The curvedsidewalls can allow for a smoother bend to be formed in the rod, canallow a greater degree of bending to be applied to the rod, or can allowa pre-bent rod to be inserted into the recess 218.

The base portion 214 can have an elevated height to align the rod recess218 of the first half-pipe 208 with a corresponding rod recess 220 ofthe second half-pipe 210. The base portion 214 can have opposed lateralflanges 222 with openings 224 formed therein for receiving fasteningelements 226 to couple the base portion to the worm gear 206. Thefastening elements 226 can be bolts, screws, press-fit pins, or otherdevices for attaching the base portion 214 to the worm gear 206. Thebase portion 214 can also be welded to the worm gear 206 or formedintegrally therewith. The half-pipe can include fillets 228 extendingbetween the arms of the top portion 216 and the flanges 222 of the baseportion 214 to help evenly distribute forces that are imparted on thehalf-pipe 208.

The base portion 214 and the top portion 216 can be a single, monolithiccomponent, as shown in FIGS. 2D-2E, or can be separate components asshown in FIGS. 2F-2G. In the latter configuration, the base portion 214can include a throughbore 230 formed therein for receiving a center axle232 about which the top portion 216 can rotate relative to the baseportion. A nut 234 can be threaded onto the center axle 232 to securethe construct to the worm gear 206. The top portion 216 can include acylindrical protrusion 236 configured to be rotatably received within acorresponding cylindrical recess 238 formed in the base portion 214.This interface can relieve stresses from the center axle 232 and canensure a secure connection is formed between the top portion 216 and thebase portion 214. The center axle 232 can have a diameter that is lessthan the diameter of throughbore 230, which can create a loose fitbetween the center axle and the throughbore that allows for smoothpivoting of the top portion 216 relative to the base portion 214.

The second half-pipe 210 can include any of the features of the firsthalf-pipe 208 discussed above, and can be attached to or formedintegrally with the chassis 202.

In use, as shown in FIG. 2H, the worm gear 206 can be rotated toposition the half-pipes 208, 210 with respect to one another such that arod R to be bent can be inserted into both of the half-pipes. Once therod R is secured within the half-pipes 208, 210, the worm gear 206 canbe rotated to form a bend in the rod. FIG. 2I shows a bend being formedin the rod R using the monolithic first half-pipe 208 of FIGS. 2D-2E.FIG. 2J shows a bend being formed in the rod R using the pivoting firsthalf-pipe 208 of FIGS. 2F-2G. The pivoting half-pipe can, in at leastsome embodiments, allow for a greater degree of bending to be applied tothe rod or for a smoother or more gradual bend to be formed as comparedwith the non-pivoting half-pipe.

FIGS. 3A-3B illustrate another exemplary embodiment of an instrument 300for bending and/or cutting an implant. Except as indicated below and aswill be readily appreciated by one having ordinary skill in the art, thestructure and function of the instrument 300 is substantially the sameas that of the instrument 100 described above, and therefore a detaileddescription is omitted here for the sake of brevity.

As shown for the instrument 300, a conical gear set can be used insteadof or in addition to the worm drives described above to convert therotational input of the driver tool into movement of a first rod holderwith respect to a second rod holder. The instrument 300 can include ashaft 302, a first conical gear 304, a second conical gear 306, a firstrod holder 308, a second rod holder 310, and an axle 312.

The first conical gear 304 can be rotatably mounted to the shaft 302,such that actuation of a driver tool 400 coupled to the instrument 300is effective to rotate the first conical gear 304 without rotating theshaft 302. The second conical gear 306 can be rotatably mounted to theaxle 312, such that the teeth of the first conical gear 304 and theteeth of the second conical gear 306 are enmeshed. Accordingly, rotationof the first conical gear 340 about an axis R1 can be effective torotate the second conical gear 306 about an axis R2 that isperpendicular or substantially perpendicular to the axis R1.

The first rod holder 308 can be mounted to the second conical gear 306.The second rod holder 310 can be mounted directly to the driver tool 400or to an intermediate chassis (not shown). While cylindrical, full-piperod holders 308, 310 are shown, it will be appreciated that any of therod holders described above can be used instead or in addition (e.g.,orbiting rollers, lid-type rod holders, pivoting or fixed half-pipe rodholders, and/or combinations thereof).

In use, a rod R can be secured to the instrument 300 using the first andsecond rod holders 308, 310 and the driver tool 400 can be actuated torotate the conical gear system 304, 306 to form a bend in the rod. Asshown in FIG. 3B, the instrument 300 can include markings or indicia fordisplaying to the user the degree to which the rod R has been bent. Forexample, a series of bend angle markings can be printed, engraved orotherwise formed on the second conical gear 306 to illustrate to theuser the degree of bending.

FIG. 4 illustrates an exemplary embodiment of a driver tool 400 that canbe used with any of the instruments disclosed herein. The driver tool400 generally includes a handle portion 402 with first and secondactuation buttons 404, 406, a non-rotating mating portion 408 configuredto mate the driver tool 400 with a chassis of an instrument (e.g., theinstruments 100, 200, 300 described herein), and a rotating component410 configured to mate with and rotate the drive shaft of an instrument(e.g., the instruments 100, 200, 300 described herein). The rotatingcomponent 410 can be driven by a motor and a power source (e.g., abattery) disposed in the driver tool 400. In some embodiments, one ofthe actuation buttons 404, 406 can be depressed to rotate the rotatingcomponent 410 clockwise and the other of the actuation buttons 404, 406can be depressed to rotate the rotating component counterclockwise.Other exemplary driver tools include the Colibri II System (a compactand modular Li-Ion-battery-driven power tool) available from DePuySynthes.

It should be noted that while devices and methods for bending or cuttingrods are disclosed herein, the instruments 100, 200, 300 can be used tobend various types of orthopedic hardware, for example, plates, cables,implants, etc. It should also be noted that while use of a power drivertool to drive rotation of the instruments is generally contemplatedherein, in other embodiments the drive shaft can be rotated manually.Any ordering of method steps expressed or implied in the descriptionabove or in the accompanying drawings is not to be construed as limitingthe disclosed methods to performing the steps in that order. Rather, thevarious steps of each of the methods disclosed herein can be performedin any of a variety of sequences. In addition, as the described methodsare merely exemplary embodiments, various other methods that includeadditional steps or include fewer steps are also within the scope of thepresent disclosure.

As evident from the foregoing, in at least some embodiments, theinstruments disclosed herein can provide one or more advantages ascompared with other instruments:

The instruments 100, 200, 300 can provide quicker and more efficientbending and/or cutting of rods.

The instruments 100, 200, 300 can be small and portable which can allowthem to be brought closer to the patient and surgical site to bend orcut a rod without leaving the patient or to bend or cut a rod that is atleast partially implanted in the patient.

The instruments 100, 200, 300 can be driven by power tools and canrequire less input force, reducing surgeon fatigue and strengthrequirements.

The instruments 100, 200, 300 can allow for precise and repeatablebending of rods.

The instruments 100, 200, 300 can allow for bending of rods to a desiredshape in fewer iterations, reducing the risk of lowered rod fatiguestrength.

The instruments disclosed herein can be constructed from any of avariety of known materials. Exemplary materials include those which aresuitable for use in surgical applications, including metals such asstainless steel, polymers such as PEEK, ceramics, carbon fiber, and soforth. The various components of the instruments disclosed herein can berigid or flexible. One or more components or portions of the instrumentcan be formed from a radiopaque material to facilitate visualizationunder fluoroscopy and other imaging techniques, or from a radiolucentmaterial so as not to interfere with visualization of other structures.Exemplary radiolucent materials include carbon fiber and high-strengthpolymers.

The devices and methods disclosed herein can be used inminimally-invasive surgery and/or open surgery. While the devices andmethods disclosed herein are generally described in the context ofbending a rod or bone plate in spine or trauma surgery, it will beappreciated that the methods and devices disclosed herein can be usedwith any human or animal implant, in any of a variety of surgeriesperformed on humans or animals, and/or in fields unrelated to implantsor surgery.

Although specific embodiments are described above, it should beunderstood that numerous changes may be made within the spirit and scopeof the concepts described. Accordingly, it is intended that thisdisclosure not be limited to the described embodiments, but that it havethe full scope defined by the language of the following claims.

1. An instrument for bending an implant, comprising: a chassis having adrive shaft disposed therein, the drive shaft being configured to rotatea gear rotatably mounted to the chassis; a first rod holder mounted onthe gear and configured to receive a portion of an implant therein; anda second rod holder mounted on the chassis and configured to receive aportion of an implant therein; wherein rotation of the gear causes thefirst rod holder to move relative to the second rod holder to form abend in an implant received in the first and second rod holders.
 2. Theinstrument of claim 1, wherein the drive shaft rotates about a firstaxis and the gear rotates about a second axis, the second axis beingperpendicular to a plane in which the first axis lies.
 3. The instrumentof claim 1, wherein the gear comprises a worm gear and wherein the driveshaft includes a worm screw configured to rotate the worm gear when thedrive shaft rotates.
 4. The instrument of claim 1, wherein the gearcomprises a first conical gear and wherein the drive shaft comprises asecond conical gear enmeshed with the first conical gear.
 5. Theinstrument of claim 1, wherein the first rod holder comprises a mainroller and a secondary roller configured to orbit the main roller whenthe gear rotates.
 6. The instrument of claim 5, wherein at least one ofthe main roller and the secondary roller includes an annular grooveformed therein for receiving an implant.
 7. The instrument of claim 5,wherein at least one of the main roller and the secondary rollerincludes a plurality of arcuate portions, each arcuate portion having adifferent radius of curvature.
 8. The instrument of claim 5, furthercomprising a cutting plate having an implant opening formed therein,wherein the main roller includes an implant opening formed therein, andwherein rotation of the main roller relative to the cutting plate iseffective to cut an implant extending through the implant openings ofthe main roller and the cutting plate.
 9. The instrument of claim 1,wherein the first rod holder comprises a half-pipe fixedly mounted tothe gear.
 10. The instrument of claim 1, wherein the first rod holdercomprises a half-pipe rotatably mounted to the gear.
 11. The instrumentof claim 1, wherein the second rod holder comprises first and secondmounts with a lid pivotally attached thereto.
 12. The instrument ofclaim 11, wherein the first and second mounts include respective rodseats, and wherein the lid has an open position in which an implant canbe freely moved with respect to the rod seats and a closed position inwhich the lid holds the implant in contact with the rod seats.
 13. Theinstrument of claim 11, wherein the lid includes opposed pivot pegs thatslide within respective slots formed in the first and second mounts. 14.The instrument of claim 11, wherein the lid includes opposed lockingpegs that are received within respective first recesses of the first andsecond mounts when the lid is in the open position and that are receivedwithin respective second recesses of the first and second mounts whenthe lid is in the closed position.
 15. A method of bending an implantusing a bending instrument having a drive shaft, a gear, and first andsecond rod holders, the method comprising: positioning the implant suchthat it is received in the first and second rod holders; and rotatingthe drive shaft to cause the gear to rotate; wherein rotation of thegear causes the first rod holder to move relative to the second rodholder to form a bend in the implant.
 16. The method of claim 15,wherein the first rod holder comprises a main roller and a secondaryroller and wherein rotating the gear causes the secondary roller toorbit the main roller to bend the implant disposed therebetween.
 17. Themethod of claim 16, further comprising selecting one of a plurality ofarcuate portions of the main roller and positioning the selected arcuateportion in contact with the implant before bending the implant.
 18. Themethod of claim 15, further comprising cutting the implant by insertingthe implant through a first opening formed in an axle portion of thegear and a second opening formed in a cutting plate of the instrumentand then rotating the gear relative to the cutting plate.
 19. The methodof claim 15, wherein positioning the implant in the second rod holdercomprises closing a lid of the second rod holder over the implant tolock the implant to first and second seat portions of the second rodholder.
 20. The method of claim 15, wherein the first rod holdercomprises a half-pipe and wherein rotating the gear causes the half-pipeto pivot relative to the gear as the implant is bent.